But you haven't allowed for the fact that Ms. Mack Truck, from an early age was looked at differently than Ken's Barbie. It is unimaginable that these kinds of experience (especially in our era of extremely high value on perfectionist sexual images) did not have a profound effect on her attitudes toward boys, men, and women. Most Lesbians (maybe all) are "lesbians by default," ---They desperately want someone to hug them and hold them close, but they perceive the chances of that happening with a male human as essentially zero, so they get affection where they can find it--a dog, a cat, or a female human.
That's a valid observation but in this case she certainly had opportunities for sexual relations with the opposite sex including me. She is delightful to be around, intelligent and the first to help someone in need. You may be correct in her case but I doubt it.
I do know of a very attractive woman who became a lesbian because of environmental considerations but she also exhibited other signs of the stresses that she had experienced. The woman in the first case seems to have none of those symptoms.